Wide bandgap mesoporous hematite nanowire bundles as a sensitive and rapid response ethanol sensor. (22nd March 2016)

• Record Type: Journal Article
• Authors: Li, Danping; Zhang, Beibei; Xu, Jingcai; Han, Yanbing; Jin, Hongxiao; Jin, Dingfeng; Peng, Xiaoling; Ge, Hongliang; Wang, Xinqing
• Is Part Of: Nanotechnology. Volume 27:Number 18(2016)
• Publication Date: 2016-03-22
• Subjects: hematite nanowires -- nanocasting -- gas sensitivity -- bandgap; Nanotechnology -- Periodicals; Nanotechnology -- Periodicals; Nanotechnology; Publications périodiques; Nanotechnologies; Periodicals; 620.5
• DOI: 10.1088/0957-4484/27/18/185702
• Languages: English
• ISSNs: 0957-4484

Abstract

Abstract: In this study, α -Fe2 O3 nanowires were synthesized using mesoporous SBA-15 silica as the hard templates with the nanocasting method, and then mesoporous α -Fe2 O3 nanowire bundles (NWBs) were separated from the well-dispersed α -Fe2 O3 nanowires (NWs) by the centrifugation technique. Both samples were characterized by x-ray diffraction, transmission electron microscopy (TEM), nitrogen adsorption/desorption isotherm and UV-vis spectra. All results indicated that the α -Fe2 O3 NWBs with mesoporous structure presented a higher BET surface area (95 m 2 g −1 ) and wider bandgap (2.08 eV) than those of α -Fe2 O3 NWs (32 m 2 g −1 and 1.91 eV). The bandgap of α -Fe2 O3 NWBs was in accordance with the bulk α -Fe2 O3, while the BET surface area was much higher. The results from the gas-sensing measurement revealed that the α -Fe2 O3 NWBs based gas sensor exhibited a high sensitivity of 21.7, fast response-recovery of 7.5 s and 1 s, and good selectivity to ethanol at 340 °C. The sensitivity (21.7) for ethanol of α -Fe2 O3 NWBs was much better than that of the α -Fe2 O3 NWs (12.2), which should be attributed to the higher BET surface area and wider bandgap of α -Fe2 O3 NWBs.